The Image class represents a single image from one of the Leap Motion cameras. More...
Inherits Interface.
Public Types | |
enum | FormatType |
Enumerates the possible image formats. More... | |
Public Member Functions | |
int | bytesPerPixel () const |
The number of bytes per pixel. More... | |
const unsigned char * | data () const |
The image data. More... | |
void | data (unsigned char *dst) const |
void * | dataPointer () const |
const float * | distortion () const |
The distortion calibration map for this image. More... | |
void | distortion (float *dst) const |
int | distortionHeight () const |
The distortion map height. More... | |
void * | distortionPointer () const |
int | distortionWidth () const |
The stride of the distortion map. More... | |
FormatType | format () const |
The image format. More... | |
int | height () const |
The image height. More... | |
int32_t | id () const |
The image ID. More... | |
Image (ImageImplementation *) | |
Image () | |
Constructs a Image object. More... | |
bool | isValid () const |
Reports whether this Image instance contains valid data. More... | |
bool | operator!= (const Image &) const |
Compare Image object inequality. More... | |
bool | operator== (const Image &) const |
Compare Image object equality. More... | |
float | rayOffsetX () const |
The horizontal ray offset. More... | |
float | rayOffsetY () const |
The vertical ray offset. More... | |
float | rayScaleX () const |
The horizontal ray scale factor. More... | |
float | rayScaleY () const |
The vertical ray scale factor. More... | |
Vector | rectify (const Vector &uv) const |
Provides the corrected camera ray intercepting the specified point on the image. More... | |
int64_t | sequenceId () const |
The image sequence ID. More... | |
int64_t | timestamp () const |
Returns a timestamp indicating when this frame began being captured on the device. More... | |
std::string | toString () const |
A string containing a brief, human readable description of the Image object. More... | |
Vector | warp (const Vector &xy) const |
Provides the point in the image corresponding to a ray projecting from the camera. More... | |
int | width () const |
The image width. More... | |
Static Public Member Functions | |
static const Image & | invalid () |
Returns an invalid Image object. More... | |
Friends | |
std::ostream & | operator<< (std::ostream &, const Image &) |
Writes a brief, human readable description of the Image object. More... | |
The Image class represents a single image from one of the Leap Motion cameras.
In addition to image data, the Image object provides a distortion map for correcting lens distortion.
Note that Image objects can be invalid, which means that they do not contain valid image data. Get valid Image objects from Frame::frames(). Test for validity with the Image::isValid() function.
enum FormatType |
Enumerates the possible image formats.
The Image::format() function returns an item from the FormatType enumeration.
Enumerator | |
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INFRARED | |
IBRG |
Image | ( | ImageImplementation * | ) |
Image | ( | ) |
Constructs a Image object.
An uninitialized image is considered invalid. Get valid Image objects from a ImageList object obtained from the Frame::images() method.
int bytesPerPixel | ( | ) | const |
The number of bytes per pixel.
Use this value along with Image::width()
and Image:::height()
to calculate the size of the data buffer.
const unsigned char* data | ( | ) | const |
The image data.
The image data is a set of 8-bit intensity values. The buffer is Image::width() * Image::height() * Image::bytesPerPixel()
bytes long.
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const float* distortion | ( | ) | const |
The distortion calibration map for this image.
The calibration map is a 64x64 grid of points. Each point is defined by a pair of 32-bit floating point values. Each point in the map represents a ray projected into the camera. The value of a grid point defines the pixel in the image data containing the brightness value produced by the light entering along the corresponding ray. By interpolating between grid data points, you can find the brightness value for any projected ray. Grid values that fall outside the range [0..1] do not correspond to a value in the image data and those points should be ignored.
The calibration map can be used to render an undistorted image as well as to find the true angle from the camera to a feature in the raw image. The distortion map itself is designed to be used with GLSL shader programs. In non-realtime contexts, it may be more convenient to use the Image::rectify() and Image::warp() functions.
If using shaders is not possible, you can use the distortion map directly. This can be faster than using the warp()
function, if carefully optimized:
Distortion is caused by the lens geometry as well as imperfections in the lens and sensor window. The calibration map is created by the calibration process run for each device at the factory (and which can be rerun by the user).
Note, in a future release, there may be two distortion maps per image; one containing the horizontal values and the other containing the vertical values.
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int distortionHeight | ( | ) | const |
The distortion map height.
Currently fixed at 64.
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int distortionWidth | ( | ) | const |
The stride of the distortion map.
Since each point on the 64x64 element distortion map has two values in the buffer, the stride is 2 times the size of the grid. (Stride is currently fixed at 2 * 64 = 128).
FormatType format | ( | ) | const |
The image format.
int height | ( | ) | const |
The image height.
int32_t id | ( | ) | const |
The image ID.
Images with ID of 0 are from the left camera; those with an ID of 1 are from the right camera (with the device in its standard operating position with the green LED facing the operator).
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Returns an invalid Image object.
You can use the instance returned by this function in comparisons testing whether a given Image instance is valid or invalid. (You can also use the Image::isValid() function.)
bool isValid | ( | ) | const |
Reports whether this Image instance contains valid data.
bool operator!= | ( | const Image & | ) | const |
bool operator== | ( | const Image & | ) | const |
float rayOffsetX | ( | ) | const |
The horizontal ray offset.
Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].
float rayOffsetY | ( | ) | const |
The vertical ray offset.
Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].
float rayScaleX | ( | ) | const |
The horizontal ray scale factor.
Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].
float rayScaleY | ( | ) | const |
The vertical ray scale factor.
Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].
Provides the corrected camera ray intercepting the specified point on the image.
Given a point on the image, rectify()
corrects for camera distortion and returns the true direction from the camera to the source of that image point within the Leap Motion field of view.
This direction vector has an x and y component [x, y, 0], with the third element always zero. Note that this vector uses the 2D camera coordinate system where the x-axis parallels the longer (typically horizontal) dimension and the y-axis parallels the shorter (vertical) dimension. The camera coordinate system does not correlate to the 3D Leap Motion coordinate system.
uv | A Vector containing the position of a pixel in the image. |
int64_t sequenceId | ( | ) | const |
The image sequence ID.
int64_t timestamp | ( | ) | const |
Returns a timestamp indicating when this frame began being captured on the device.
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Provides the point in the image corresponding to a ray projecting from the camera.
Given a ray projected from the camera in the specified direction, warp()
corrects for camera distortion and returns the corresponding pixel coordinates in the image.
The ray direction is specified in relationship to the camera. The first vector element corresponds to the "horizontal" view angle; the second corresponds to the "vertical" view angle.
The warp()
function returns pixel coordinates outside of the image bounds if you project a ray toward a point for which there is no recorded data.
warp()
is typically not fast enough for realtime distortion correction. For better performance, use a shader program executed on a GPU.
xy | A Vector containing the ray direction. |
int width | ( | ) | const |
The image width.